View Full Version : Precious Metal Clay (PMC)

06-18-2001, 01:22 AM
I just wrote about this in my online journal, but I figured you all might find it very interesting, too... sculpting clay and turning it into silver. The alchemists of old would be thrilled.

<a href="http://www.beware-of-art.com/journal/200106/18_05002.jpg"><img src="http://www.beware-of-art.com/journal/200106/18_05002_300x220.jpg" border="0"><br>Click for a larger view</a>
The center pendant is the original, and the outer two are "prints" of the original.

I've just discovered this very interesting stuff called PMC (Precious Metal Clay). Here's a link to the <a href="http://www.pmcguild.com/" target="_new">PMC Guild website</a>. PMC is basically silver particles in an organic binder... you work it like regular clay, then toss it in a kiln. The binder burns out, leaving you with an object made of .999 pure silver (purer than sterling!). There's also a softer version that comes in a syringe that you can use to write fine lines on the surface of the work. AND, get this -- there's a paper-like sheet of the stuff, too. Origami artists are using it to make pure silver origami. Apparently PMC shrinks a bit as it is fired.

PMC comes in 24 karat gold too, but of course that's INSANELY expensive ($200ish for a lump the size of the tip of my little finger! Ouch!). As it is, a wad of the silver clay that's about the size of an oval grape costs $30. I've been wanting to try it out anyway, to use some of this in my artwork... maybe as wings on wearable sculpture insects, or maybe with fossil-type imprints.

So, I ordered some.

I worked on some test silver slab pendants last night, fired them up today. I carved and stamped the design into the surface of the slab. On the back it has my initials JDLC, 05002, and my thumbprint. Too bad the print doesn't show. Here's the pendant, <a href="http://www.beware-of-art.com/journal/200106/16_05002_alone.jpg">number 05002</a>. It's exactly an inch tall. It's bright shiny silver because I hadn't applied the black patina yet (see the picture at the top of this post for what it looks like with patina).

Here's <a href="http://www.beware-of-art.com/journal/200106/18_05001.jpg">another tiny test I made</a>, just a little over a half inch tall.

Neat, huh? Too bad it's pricey. I figured you all would find it interesting, regardless... :D

-=- Jen "Silver pusher" de la Cruz

06-18-2001, 02:21 PM
Wow! What a brilliant idea! Thanks for posting this - I'd never heard of this stuff before.

Do you have a kiln? I only have access to one when I am doing clay sculpting at my evening class. I'm not sure how they would feel about firing anything different - I wonder if it needs different temperatures to regular clay. And then there's the security aspect.

best wishes

06-18-2001, 04:01 PM
I do have a kiln (luckily).

For PMC+, the new fast-firing formulation, it's something like this...
10 minutes at 1650 fahrenheit
20 minutes at 1550
30 minutes at 1450.

You can't overfire it apparently -- as long as it stays below 1650, it can stay in the kiln for hours if necessary. It's nontoxic and I bet you could convince some ceramicist to fire it along with their ceramics. It's not like it will explode in the kiln like badly-done ceramics will...

I heard about somebody who'll fire PMC for $1 a piece (plus $3.95 per package to send it back). I'll try and find that info again.

Also something I didn't mention -- when it comes out of the kiln it has a powdery white surface. That's silver particles, basically. So it needs to be buffed or burnished to turn out silver. There's mechanical ways to do this (tumblers etc) but I just burnished mine by hand with a wire brush, it was very easy.

-=- Jen "I'll get back to you" de la Cruz

06-18-2001, 04:04 PM
Here it is! It was under the Links section on pmcguild.com...

"Certified instructor with Paragon kiln will fire your silver PMC/PMC+ work for $1 per piece. For out-of-area service, please add $3.95 return postage (Priority Mail, up to 2 lbs.). Additional s/h charges will apply to packages over 2 lbs. Pieces should be thoroughly dry before wrapping and carefully packaged to avoid breakage or cracking of clay. Include name, address and phone number and mail with check or money order to:
BEADANGLED, P.O. Box 86015, Tucson, AZ 85754.
For more information, contact Lyle Rayfield at 520-682-8325 or e-mail her at bdangled@dakotacom.net "

-=- Jen "Fire at will!" de la Cruz

06-18-2001, 04:33 PM


And it looks like it is available in the UK, too. Although only in silver I think. (silver alchemy (http://www.silveralchemy.com/home.html))

As for convincing the college ceramicist ... ahem. We are lucky to get our sculptures fired (well, they're not pots, are they!) :rolleyes:

06-18-2001, 08:53 PM
I wouldn't be surprised if Rio Grande jewelry supply was willing to ship overseas. Failing that, you could get somebody else to act as an intermediary for you and then THEY ship it to you.

The gold clay is just too expensive for me right now. Maybe I'll get my silver jewelry gold-plated (vermeil).

One thing RE: Silver Alchemy. Make sure you know whether you're getting PMC or PMC+. It makes a world of difference in terms of shrinkage and firing time!

-=- Jen "Don't fire until you see the whites of their clay!" de la Cruz

06-19-2001, 10:27 AM
Wow Jen this looks like great stuff.
Glad you posted it :)

06-19-2001, 02:24 PM
Thanks, Jen. This sounds like fun. I do ceramic sculpture, and I have a kiln (not yet hooked up, but sitting in my studio/garage, which I just found out has termites, sigh). I have always been fascinated by jewelry design (my grandma did it professionally), but I can't find a class in this area to learn about working with regular materials. This sounds like just the thing to play with in the meantime!


06-19-2001, 07:19 PM
The reference book I always end up going back to for jewelry work is:
"The Complete Metalsmith: An Illustrated Handbook" by Tim McCreight
ISBN: 0-87192-240-1

It's only $12 on Amazon.com and it has a 5/5 star rating. :D

-=- Jen "I plug everything... and oh hey look, I just noticed my evil smiley is back! YAY!" de la Cruz
:evil: :evil: :evil: :evil: :evil: :evil: :evil: :evil: :evil:

06-20-2001, 08:01 PM
Thanks. I will check out the book -- my husband may have it since he used to do blacksmithing. (If you're wondering why I don't ask him to teach me the ropes, lets just say its too close to taking driving lessons from my Dad-- a disaster waiting to happen...)


max nelson
08-09-2001, 02:13 AM
Hi Jen..I'm new to the forum but checked out your site yesterday and you are very creative. I have not heard of this material until your post. It's great for fine jewelry but as you say, pricey. Are you familiar with the product Forton? It's basicaly a modified gypsum that dries rock hard, is weather proof and can be cast with a coating of bronze, copper or silver. The finished cast is nearly indistinguishable from a solid cast but about 10% of the cost. I just cast a life sized bust using this product for the first time and was very pleased with the results. I did take a workshop on it's use first and it can be a little tricky to cast an 'in the round ' object but is great for bas reliefs or maybe for some of the items you create. The real cost savings is that the metal coating is only about 1/16 to 1/8 inch thick. It will accept cold patinas just as a solid casting does. If you need more info will be pleased to provide.

08-09-2001, 08:17 AM
Thanks for the compliments! Forton sounds like great stuff, Max, although I've never heard of it before. For sculptures larger than this jewelry, I usually use Winterstone (see my <a href="http://www.wetcanvas.com/forums/showthread.php?s=&threadid=2261">other post about Winterstone</a>).

I'm always on the lookout for new materials, hope you don't mind a couple of questions

How do you cast it with a "coating" of metal? When I work with Winterstone, if I wanted I could add metal powder to the mix and then it would accept cold patinas just like Forton apparently does.

Do you mix Forton with water, or what? Any data on how long it might last as a material (years?). That's the other thing I like about Winterstone; since it's essentially cement, there's lots of information on how long cement survives indoors and outdoors.

Is Forton only workable in a casting-type manner? I mean, can it be sculpted directly via a thicker mix, does it slump, etc?

Thanks for any info.

-=- Jen "Slump factor" de la Cruz

max nelson
08-09-2001, 08:20 PM
Hi Jen...Happy to answer your questions. Forton is a proprietary product by Ball Consulting. Main office I believe in Pittsburg but they have a distributor in Scottsdale or Chandler Az. I will get the address for you if youwant. It works very much as plaster but with the addition of a polymere liquid vs. water to activate. One inch strands of fiberglass is mixed into the mixture to add strength. The coating is a mixture 5 units of metal powder, 2 units of forton powder and 1 unit of polymere. (I will have to check my instructions to insure this is the correct mixture, since I havn't used it much yet). This metal coating is first slush cast into the mold or poured and painted onto the surface of a bas relief mold. Then the forton-fiberglass mixture added to about a 1/2 to 3/4 inch thickness for strength. As far as how long it will last outdoors it probably is not as permenant as cement but will certainly outlast one's lifetime. It is a similar procedure as the process called 'cold casting' with the exception that the body of the object is forton vs. a resin. As a consequence the object is somewhat lighter in weight. It has a very pleasing apperance even without the coating. I did a practice cast first without the addition of the metal coating to work out the bugs. After it had set, in my case only a matter of 10 or 15 minutes, I applied a colored wax paste and it looks great.

Have a good day....Max